Cooling means for clutches and brakes



2 smrs- 1 .ACHILLE CARLO SAMPIETRO KNOWN AS ACHILLES CHARLES SAMPIETRO COOLING MEANS FOR CLUTCHES AND BRAKES fivvavran 401/445 C4410 5 1 1 157770 Know/2 45 4:10:15: 6/ 415; 5 9/: 7/?0 grraelvey' Dec. 16, 1952 Filed June so, 1950 Patentecl Dec. 16, 1 952 2,622,216 oooL'ING MEANs FoaoLU'rcHEs AND BRAKES c'iiillefflarlofsamn known a Ac le *Charles'sampietro, London, England, assignor tofD. R. Rkibertson Limited, London, England,

a company of Great Britain nisiiiicaiidi iiihe 30, 1950, Serial No. 171,312 InGreat Britain July 4, 1949 4 Claims. 1 This invention relates to slip couplings for use asclutches or brakes for transmitting or'restraining rotary motion, and of the kind having a rotary member which is heated as a result'of operation of the coupling and which is accommodated in a fixed casing. v I

A first object of this invention is to provide such a coupling with self -contained cooling means employing the surrounding atmosphere as the coolingmedium. p

A second object is to provide in an electromagnetic coupling a construction of rotary member which consists partly of magnetic material and partly of a metal of relatively high heat conductivity so as to increase the heat dissipation capacity of the rotary member.

A third object is to prevent the parts of such a built-up rotary member from becoming loose with respect to one another as a result of changes of temperature.

According to this invention, in a coupling of the kind hereinbefore specified, the rotary memher is provided at at least one of its sides with impeller vanes co-operating with a centrifugal fan chamber formed in the side of thefixed casing, the fan chamber is provided with a plurality of delivery ducts distributed around the casing and having outlets shaped to discharge air in directions having components directed radially inwards against the periphery of the rotary member, and the casing is provided with exhaust ports which are distributed around the casing in alternation with the outlets of the delivery ducts. The periphery of the rotary member is preferably provided with circumferentially disposed cooling fins.

When the coupling is of the electromagnetic type and the rotary member includes an annular armature, the rotary member may be built up from a drum of a material of relatively high heat conductivity, e. g. an aluminium or magnesium base alloy (hereinafter termed a light alloy), carrying the impeller vanes and provided with integral circumferential cooling fins, this drum being shrunk onto the annular armature.

In such a built-up construction embodying a light alloy drum having a cylindrical bore into which the annular armature is fitted, the armature may be locked to the drum by rivets, consisting wholly or largely of copper and in a harddrawn condition, disposed parallel to the coupling axis through bores in an end wall of the drum and in the armature.

One example of the invention as applied to an electromagnetic coupling of the eddy-current type will now be described, by way of example, with *2 reference to the accompanying diagrammatic drawings wherein; I r v Figs. 1 and2 are sections taken on thelines 1-1 and '22 respectively in Fig. '3 and Fig.3 is an end view of the coupling.

The driven coupling member I'll where the coupling is used as a clutch (or the stationary member it! where the coupling'i's'usedas abr'ake) is an annular "electfomagnet oi channel section arranged with the channel opening 'radially'outwards; The m'agnetcontains'an'exciting coil H for connection to a D. Cfsource. At the periphery of each side wall of the channel is'a ring of uniformly spaced pole-pieces IZjthenumbers of "polepieces in the two rings being the same. The'p'olepieces of one ringarest'aggered with respect to those of the other. Each pole-piece includes a finger l3 projecting over'the' mouth of the channel to a distance such'that the fingers of one ring interlace with those of 'the' other. Allthe pole faces lie in a common spherical belt I 4.

The rotary member includes a hollow armature l5 enveloping the two rings of pole-piecsand fitted in a cylindrical bore in a light'alloy rim It provided with circumferential cooling fins IT. This rim is is rigid with a light 'alloyfia'nge 18, the rim and flange together forming a drum coupled to a driving member. At each side of the rotary member near its periphery is a ring of radial-flow impeller vanes 20, which are integral with the rim IS.

A fixed casing 2i consists of two light alloy castings joined at a plane containing the coupling axis and together forming a drum-shaped body. At each end of the casing is a central aperture 22 by which air is admitted to the eyes of the impellers. Each impeller 28 discharges into a series of like delivery ducts uniformly distributed around the casing. Each duct has an inlet por-- tion 23 corresponding to part of the diffuser or volute chamber of a conventional centrifugal fan and leading radially outwards. An intermediate portion of each duct leads helically outside the rotary member to an outlet port 24 directing air radially inwards onto the finned rim of the rotary member. The two series of ducts are symmetrically arranged, and each cools one half of the width of the rim. Between the outlet ports of the ducts the casing is provided with exhaust ports 25 by which the heated air is discharged radially outwards. The exhaust ports are provided with gauze covers 23.

The rim it of the rotary member and the hollow cylindrical armature l5 are divided into two parts and each half-rim is shrunk onto its respective half-armature the two parts being locked together by hard-drawn copper rivets such as 26 fitted in holes bored in the axial direction through the half-armatures and through radially depending integral flanges on the half-rims. The two half-assemblies are fastened together by bolts such as 21 also fitted in holes bored in the axial direction through the armature l5 and the radially depending flanges on the rim l 6. With the specified combination of materials, there is considerable latitude in design in the ratio of the axial dimensions of the light-alloy and iron parts accommodating the rivets; nevertheless the rivets do not work loose as a result of expansion and contraction of the parts due to variations in temperature.

Iclaim:

1. A coupling for use as clutch or brake for transmitting or restraining rotary motion, and of the kind having a, rotary member which is heated as a result of operation of the coupling and which is accommodated in a fixed casing, the rotary member being provided at at least one of its sides with impeller vanes co-operating with a centrifugal fan chamber formed in the side of the fixed casing, the fan chamber being provided with a plurality of delivery ducts distributed around the casing and having outlets shaped to discharge air radially inwards against the periphery of the rotary member, and the casing being provided with exhaust ports which are distributed around the casing in alternation with the outlets of the delivery ducts whereby the air discharged radially inwards against the periphery of the rotary member moves circumferentially of the rotor during its passage from the delivery ducts to the exhaust ports.

2. A coupling for use as a clutch or brake for transmitting or restraining rotary motion, and

of the kind having a rotary member which is heated as a result of operation of the coupling and which is accommodated in a fixed casing, the periphery of the rotary member being provided with oircumferentially disposed cooling fins, the rotary member being provided at at least one of its sides with impeller vanes co-operating with a centrifugal fan chamber formed in the side of the fixed casing, the fan chamber being provided with a plurality of delivery ducts distributed around the casing and having outlets shaped to discharge air radially inwards against the periphery of the rotary member, and the casing being provided with exhaust ports which are distributed around the casing in alternation with the outlets of the delivery ducts whereby the air discharged radially inwards against the periphery of the rotary members moves circumferentially of the rotor during its passage from the delivery ducts to the exhaust ports.

3. A coupling as claimed in claim 1 and of the electromagnetic type, the rotary member including an annular armature and being built up from a drum of a material of relatively high heat conductivity, carrying the impeller vanes and provided with integral circumferential cooling fins, this drum being shrunk onto the annular armature.

4. A coupling as claimed in claim 3 wherein the drum has a cylindrical bore into which the an-- nular armature is fitted, the armature being locked to the drum by rivets, consisting at least largely of copper and in a hard-drawn condition, disposed parallel to the coupling axis through bores in an end wall of the drum and in the armature.

ACHILLE CARLO SAMPIETRO, Known as Achilles Charles Sampietro.

REFERENCES CITED lhe following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,409,557 Gilfillan Oct. 15, 1946 2,503,704 Bessiere Apr. 11, 1950 FOREIGN PATENTS Number Country Date 692,712 France Aug. 5, 1930 458,332 Germany Apr. 4, 1928 

